Lost the workspace menu...how to get it back?
File New General Click Default View port ...

or

Blender Open another file ... and a menu may be created ...

When you first start Blender
Blender has a program folder and a user settings folder. If you delete the default settings folder, Blender will run by default. Windows 10 exists in the app data folder. I don't know Linux. If it's resolved, you'll find Save Blender Default Startup in the Blender File menu. Be sure to save it and work with it.